Horizontal gene transfer of the pirAB genes responsible for Acute Hepatopancreatic Necrosis Disease (AHPND) turns a non- Vibrio strain into an AHPND-positive pathogen

In the past decade, shrimp farms, particularly those established in Asia, Mexico and South America suffered from the outbreak of an emergent penaeid shrimp disease known as Acute Hepatopancreatic Necrosis Disease (AHNPD). The PirA and PirB toxins produced by plasmid pVA1 in were reported to cause the AHPND pathology. More recent research demonstrated that is not the only species that can cause AHPND, as other species were also found to contain PirAB-containing plasmid. The present study assessed the Horizontal Gene Transfer (HGT) of AHPND that transforms genes ( and ) from AHPND positive to non-AHPND and non-vibrio species identified as sp. strain NBP. The HGT of and genes from the AHPND positive to sp. strain NBP was found to occur at different temperatures. The conjugation efficiency rate (n°) of from to sp. strain NBP at 30°C and 40°C showed 80-91% efficiency. Shrimp challenged with the and positive sp. strain NBP also demonstrated typical pathognomonic AHPND lesions during the histopathologic examination.